update() method does not work.

[DesmondPang]

The updata() method does not work. It seems that you missed the first() after where() The where() return an array but not an unique model.

public function update(array $data, $id, $attribute="id") {
return $this->model->where($attribute, '=', $id)->update($data);
}

[DesmondPang]

Actually, they update() is not called. where($attribute, '=', $id) returns a array and it cannot pass to update().